FIG. 6 is an electrical diagram of a conventional electronic device. The electronic device includes detection device 1, pick up circuit 2, analog-digital (AD) converter 3, frequency supply circuit 4, output voltage decision circuit 7, and diagnosis signal supply circuit 8. Pick up circuit 2 detects, as a signal, physical information detected by detection device 1. Analog-digital converter 3 AD converts the signal detected by pick up circuit 2. Frequency supply circuit 4 determines the sampling frequency of analog-digital converter 3. Output voltage decision circuit 7 determines the magnitude of the output voltage of the output signal of analog-digital converter 3. Diagnosis signal supply circuit 8 supplies an analog signal for failure diagnosis to analog-digital converter 3. The self-diagnosis of the electronic device is completed when output voltage decision circuit 7 determines whether the output signal of analog-digital converter 3 which has received the analog signal is within a predetermined range. An example of a conventional technique related to the present invention is shown in Patent Literature 1.